If my buyer sells the business again and reassigns the lease, could I still end up liable?

Potentially, yes, and this is one of the more counterintuitive risks of not obtaining a full release when you originally sold. If you were never released from the lease covenants (or from a personal guarantee) and your lease doesn't limit your exposure to only the tenant immediately following you, your original liability can, in principle, continue through subsequent reassignments — meaning a default by a buyer two or three sales removed from you could still, in theory, be something the landlord tries to pursue you for, depending on exactly how your original obligations were worded.

This is a strong argument for insisting on a clean, complete release at the time you sell, rather than assuming your risk naturally tapers off once your immediate buyer takes over and moves on themselves. A release properly obtained at your own sale generally protects you from this entire chain, regardless of how many times the lease changes hands afterward.

If you're unsure whether your original assignment included a full release, it's worth confirming now. A Treadstone business lawyer can review your original documents and clarify your actual exposure.